Deuteronomy 17:6
By the mouth of two witnesses or of three witnesses is he who is dead put to death; he is not put to death by the mouth of one witness;
Numbers 35:30
whoso smiteth a person, by the mouth of witnesses doth one slay the murderer; and one witness doth not testify against a person -- to die.
Deuteronomy 19:15
'One witness doth not rise against a man for any iniquity, and for any sin, in any sin which he sinneth; by the mouth of two witnesses, or by the mouth of three witnesses, is a thing established.
Matthew 18:16
and if he may not hear, take with thee yet one or two, that by the mouth of two witnesses or three every word may stand.
2 Corinthians 13:1
This third time do I come unto you; on the mouth of two witnesses or three shall every saying be established;
1 Timothy 5:19
Against an elder an accusation receive not, except upon two or three witnesses.
Hebrews 10:28
any one who did set at nought a law of Moses, apart from mercies, by two or three witnesses, doth die,
John 8:17-18
and also in your law it hath been written, that the testimony of two men are true;